Re: [PATCH v21 10/26] x86/mm: Update pte_modify for _PAGE_COW
From: Borislav Petkov <bp@alien8.de>
Date: 2021-03-05 14:30:28
Also in:
linux-api, linux-arch, linux-mm, lkml
On Wed, Feb 17, 2021 at 02:27:14PM -0800, Yu-cheng Yu wrote:
quoted hunk ↗ jump to hunk
@@ -787,16 +802,34 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) */ val &= _PAGE_CHG_MASK; val |= check_pgprot(newprot) & ~_PAGE_CHG_MASK; + val = fixup_dirty_pte(val);
Do I see it correctly that you can do here and below:
/*
* Fix up potential shadow stack page flags because the RO, Dirty PTE is
* special.
*/
if (pte_dirty()) {
pte_mkclean();
pte_mkdirty();
}
?
That fixup thing looks grafted and not like a normal flow to me.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette